This paper presents the main experimental evaluation results of SiC MOSFET performance in a 3-phase 3-level neutral point diode clamped inverter prototype. The prototype is built with 650 V class commercially available SiC MOSFETs and Schottky diodes to assess semiconductor device performance in auxiliary converters intended for use in transportation applications. Inverter variable frequency operation in wide switching frequency range is analyzed and the acquired results show low switching losses and high efficiency with different input and output parameters. Analysis results show, that despite higher purchase costs, the SiC semiconductor devices can achieve excellent performance in transportation applications, compared to Si IGBTs. High initial price will be compensated by reduced losses throughout converter life cycle and, hence, the use of SiC devices is technically and economically effective.